LT1 build...need opinions...
02-02-2009, 04:03 PM
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LT1 build...need opinions... I have a 97z, heads have been ported and polished, intake port matched, "hot cam", and pro charger. Its running 5lbs of boost right now. Everyone has said they wont live long with much more. I intend to put the 10lb pulley on in early summer. My plan is to take the engine out and put a forged bottom end. I want to keep it streetable and pump gas. Need suggestions on compression ratios, camshaft, and whether to make it a 383, how much grinding is involved for clearancing? I plan to keep the stock heads, unless i can sell them for a good price and buy new.. Thanks
02-02-2009, 04:13 PM
#2
I have a 97z, heads have been ported and polished, intake port matched, "hot cam", and pro charger. Its running 5lbs of boost right now. Everyone has said they wont live long with much more. I intend to put the 10lb pulley on in early summer. My plan is to take the engine out and put a forged bottom end. I want to keep it streetable and pump gas. Need suggestions on compression ratios, camshaft, and whether to make it a 383, how much grinding is involved for clearancing? I plan to keep the stock heads, unless i can sell them for a good price and buy new.. Thanks
02-02-2009, 04:32 PM
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02-02-2009, 04:34 PM
#4
This will give you an idea:
http://www.golenengineservice.com/html/lt1_lt4.html
They have a built FI 383 short block for $4k, which is not that bad if you factor in machine work, stroker rotating assembly, forged parts, etc. The block has dished pistons and is listed at being capable of supporting 750 hp. I like it. Supercharger 383 long block is $8.5k.
http://www.golenengineservice.com/html/lt1_lt4.html
They have a built FI 383 short block for $4k, which is not that bad if you factor in machine work, stroker rotating assembly, forged parts, etc. The block has dished pistons and is listed at being capable of supporting 750 hp. I like it. Supercharger 383 long block is $8.5k.
02-02-2009, 08:38 PM
#5
Using a store bought short block (hey, that kind of rhymes) is certainly a choice. If you wanted to roll your own, you would have to purchase a fully forged rotating assembly (in that case you have many choices), have the block align honed, clearanced for the 383, decked, match the head surface, and probably install 4 bolt splayed mains. Along with new bearings, oil pump, lifters, etc., etc. It is a tedious process and there are lots of "gotcha"s.
The nice thing about the store bought ones are they are basically drop in. The nice thing about rolling your own is that you can select your own components. That, and you can have the piece in your signature that says "Built, not bought".
The nice thing about the store bought ones are they are basically drop in. The nice thing about rolling your own is that you can select your own components. That, and you can have the piece in your signature that says "Built, not bought".
02-02-2009, 08:50 PM
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Using a store bought short block (hey, that kind of rhymes) is certainly a choice. If you wanted to roll your own, you would have to purchase a fully forged rotating assembly (in that case you have many choices), have the block align honed, clearanced for the 383, decked, match the head surface, and probably install 4 bolt splayed mains. Along with new bearings, oil pump, lifters, etc., etc. It is a tedious process and there are lots of "gotcha"s.
The nice thing about the store bought ones are they are basically drop in. The nice thing about rolling your own is that you can select your own components. That, and you can have the piece in your signature that says "Built, not bought".
The nice thing about the store bought ones are they are basically drop in. The nice thing about rolling your own is that you can select your own components. That, and you can have the piece in your signature that says "Built, not bought".
02-03-2009, 01:01 AM
#7
There will be some machining involved for clearancing the 383. Seems like the cost was in the $500 and up range, but it's been a while and my numbers may be skewed.
I called CompCams for a turbo cam, I am pretty sure they have numbers for a blower cam as well. (Not my forte'.)
The "norm" for FI is about 9.5:1 CR.
10 pounds is pretty mild, if you do the full build you should be safe up to 15 pounds.
AFA rotating assemblies, my first choice is Callies with Diamond FI pistons with Hellfire rings. But then I saw the price differential and settled for Eagle.
The Callies cranks are manufactured in China, but the finish machining is done in the US of A.
Depending on what type of revs you want to make, and lift you want, you may consider strengthening the valve train with full RRs, high lift springs, chromoloy pushrods, the usual.
I called CompCams for a turbo cam, I am pretty sure they have numbers for a blower cam as well. (Not my forte'.)
The "norm" for FI is about 9.5:1 CR.
10 pounds is pretty mild, if you do the full build you should be safe up to 15 pounds.
AFA rotating assemblies, my first choice is Callies with Diamond FI pistons with Hellfire rings. But then I saw the price differential and settled for Eagle.
The Callies cranks are manufactured in China, but the finish machining is done in the US of A.
Depending on what type of revs you want to make, and lift you want, you may consider strengthening the valve train with full RRs, high lift springs, chromoloy pushrods, the usual.
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02-03-2009, 08:35 AM
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There will be some machining involved for clearancing the 383. Seems like the cost was in the $500 and up range, but it's been a while and my numbers may be skewed.
I called CompCams for a turbo cam, I am pretty sure they have numbers for a blower cam as well. (Not my forte'.)
The "norm" for FI is about 9.5:1 CR.
10 pounds is pretty mild, if you do the full build you should be safe up to 15 pounds.
AFA rotating assemblies, my first choice is Callies with Diamond FI pistons with Hellfire rings. But then I saw the price differential and settled for Eagle.
The Callies cranks are manufactured in China, but the finish machining is done in the US of A.
Depending on what type of revs you want to make, and lift you want, you may consider strengthening the valve train with full RRs, high lift springs, chromoloy pushrods, the usual.
I called CompCams for a turbo cam, I am pretty sure they have numbers for a blower cam as well. (Not my forte'.)
The "norm" for FI is about 9.5:1 CR.
10 pounds is pretty mild, if you do the full build you should be safe up to 15 pounds.
AFA rotating assemblies, my first choice is Callies with Diamond FI pistons with Hellfire rings. But then I saw the price differential and settled for Eagle.
The Callies cranks are manufactured in China, but the finish machining is done in the US of A.
Depending on what type of revs you want to make, and lift you want, you may consider strengthening the valve train with full RRs, high lift springs, chromoloy pushrods, the usual.
How many lbs of boost are you running? what power does it make. I might upgrade the heads while im at it just not sure yet. Already have RRs, good springs, and hardened pushrods. Of course changing everything could/will affect the PR length. 9.5:1 sounds good, i didn't know, always heard to run lower compression, bigger end gap on the rings as well. Do you have splayed main caps? are LT1 mains not strong enough? Thanks much for the advice
02-03-2009, 09:08 AM
#9
The engine install is awaiting good weather (currently snowing as I type).
Should be good for 475-500 rwhp at 8 p.s.i. with meth injection. With stock internals and 7 p.s.i. (no meth) it was right at 400 rwhp.
An intercooler will allow higher boost, I'm going to 12 p.s.i. Should be good for 550-600 rwhp. All numbers through a 4L60e, and I believe I am very conservative with the figures. The tune can greatly affect them as well. I would prefer to stay at the 600 hp level; any more and I will endanger my transmission, which becomes borderline at that range.
9.5 is the lower compression figure, stock is ~10.25:1, IIRC.
I went with the splayed caps for insurance purposes. There are those who will argue that they are not needed. Perhaps, perhaps not. IMO, I had the engine apart, why not spend a bit and build it with overkill. Better to have it and not need it than to not have it and need it. But that's just me.
AFA the heads, I concentrated there, but you already have all the good stuff. I did go with 2.02/1.60 SS Manley valves. I wanted it to breathe as much as possible, but did not go as far as CNC-porting.
Should be good for 475-500 rwhp at 8 p.s.i. with meth injection. With stock internals and 7 p.s.i. (no meth) it was right at 400 rwhp.
An intercooler will allow higher boost, I'm going to 12 p.s.i. Should be good for 550-600 rwhp. All numbers through a 4L60e, and I believe I am very conservative with the figures. The tune can greatly affect them as well. I would prefer to stay at the 600 hp level; any more and I will endanger my transmission, which becomes borderline at that range.
9.5 is the lower compression figure, stock is ~10.25:1, IIRC.
I went with the splayed caps for insurance purposes. There are those who will argue that they are not needed. Perhaps, perhaps not. IMO, I had the engine apart, why not spend a bit and build it with overkill. Better to have it and not need it than to not have it and need it. But that's just me.
AFA the heads, I concentrated there, but you already have all the good stuff. I did go with 2.02/1.60 SS Manley valves. I wanted it to breathe as much as possible, but did not go as far as CNC-porting.
02-03-2009, 09:23 AM
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The pro charger i have is a P600b, twin inner coolers. I haven't read up on these much. I just know it sounds awesome The car like it is made like 476 rwhp at 5000 rpm. The cam runs out at around 6400, so i figure it should be right at 500. So if i go with 10psi i think it will gain at least another 100? probably for sure put a blower cam, call comp and let them choose it. Then i must find a place to get it tuned, i guess the closest place would be st. loius. I probably will need bigger injectors? i think it has 32#. whatever came with the pro charger kit. I have a 98 ss, heads, cam, ls6 intake, headers, 12.50's all day, and i don't even hardly look at that thing lately ha..i planned to go through that engine again, make some more power, its on the back burner now.
The car like it is made like 476 rwhp at 5000 rpm. The cam runs out at around 6400, so i figure it should be right at 500. So if i go with 10psi i think it will gain at least another 100? probably for sure put a blower cam, call comp and let them choose it. Then i must find a place to get it tuned, i guess the closest place would be st. loius. I probably will need bigger injectors? i think it has 32#. whatever came with the pro charger kit. I have a 98 ss, heads, cam, ls6 intake, headers, 12.50's all day, and i don't even hardly look at that thing lately ha..i planned to go through that engine again, make some more power, its on the back burner now.
02-03-2009, 10:50 AM
#11
Yeah, you got a whiny car. 
I got into a long conversation with one of the CC reps. He had a ~97 Formula, and we started talking fbodies. Great guy. If I find the guy's number, I'll pass it on to you.
At 476 hp, I suspect you have 42# injectors. I suggest finding out and going up a size, which would be 60#. But you would have to change the parameter immediately, prior to driving anywhere. In fact, you need to have someone look at what you have, which will be in the tune. Do you have the tune file?
Also, you will now be at the maximum for your fuel system. (It just snowballs at this point.) You will want to consider a dual-pump system. Lonnie's Performance sells an awesome system, but it is overkill for my needs. I'll be doing the MightyMouse dual system, in fact, I have already done the design and parts selection. Now in the parts procurement stage.
I got into a long conversation with one of the CC reps. He had a ~97 Formula, and we started talking fbodies. Great guy. If I find the guy's number, I'll pass it on to you.
At 476 hp, I suspect you have 42# injectors. I suggest finding out and going up a size, which would be 60#. But you would have to change the parameter immediately, prior to driving anywhere. In fact, you need to have someone look at what you have, which will be in the tune. Do you have the tune file?
Also, you will now be at the maximum for your fuel system. (It just snowballs at this point.) You will want to consider a dual-pump system. Lonnie's Performance sells an awesome system, but it is overkill for my needs. I'll be doing the MightyMouse dual system, in fact, I have already done the design and parts selection. Now in the parts procurement stage.
02-03-2009, 02:33 PM
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Dang it, yea its always something. I will find out from the guy what injectors etc. i have. I know he put another fuel pump on it as well that come with the pro charger. Seem like alot of work, but i sure want the 10lb pulley on there
we'll just have to see how it goes. Also then i got the problem of finding someone to tune it, i know that needs to be done immediately after putting the engine back in right?
we'll just have to see how it goes. Also then i got the problem of finding someone to tune it, i know that needs to be done immediately after putting the engine back in right? 
